Static eliminator for radio telegraphy



Nov. 16, 1943. T. w. HOLDEN STATIC ELIMINATOR FOR RADIO TELEGRAPHY Patented Nov. 16, 1943 UNITED STATES, PATENTaOFFlCE STATIC ELIMINATOR FOR RADIO TELEGRAPHY Thomas W.- Holden, Fort Wayne, Ind. Application August 18, 1941, Serial No. 407,343

1 Claim.

This invention relates to improvements in static eliminators for radio telegraphy, and an object of the invention is to provide in connection with a radio telegraphic receiver an adjunct capable of diverting from the received radio current, such as passes through an antenna circuit, detrimental influences that generally are caused by inherent radio electrical disturbances or forces or differ ent frequencies.

Another object of the invention is to afford, in an adjunct for a radio telegraphic receiver, a circuit including a coil influenced by the output current from a telegraphic receiver, over which is carried a normal signal and including the static disturbances, a second circuit including another coil influenced approximately only by the static eifect imparted through the telegraphic receiver, and a make and break mechanism influenced oppositely by the magnetic fields of said coils and connected in another circuit with a telephonic receiver.

Other objects and advantages of the invention appear in the following description.

An illustrative embodiment of the invention is shown in the accompanying drawing, in which:

Fig. 1 is a diagram showing the relative arrangement of the various parts and electrical circuits of the adjunct and a radio telegraphic receiver;

Fig. 2 is a side elevational view of an oscillating shaft and parts connected therewith forming an element of the appliance;

Fig. 3 is a fragmentary cross-sectional view, the section being on the line X--X in Fig. 1; and

Fig. 4 is a detail showing a top plan view of a make and break device associated with the audio circuit.

The illustrative embodiment of the invention consists of a radio telegraphic receiver I, of any suitable type for the transmission of code signals received through an antenna circuit, having connected therewith a primary audio circuit including conductors 2 and 3 provided with corresponding extensions thereof 2 and 3', in which are connected in series a variable resistance member 5, telephonic receiver 4 and another variable resistance member 6, in the order as named. A secondary audio circuit is provided consisting of continuations 2" and 3" of said extensions, in which secondary circuits are connected, in series,

an electrical make and break controlling device hereinafter described, and in parallel, a condenser located between said device and said resistance member 6. The controlling device consists of a standard 8 provided with a base 9,

and an oscillating shaft I9 pivotally supported in the standard, there being an adjusting screw II in the standard engaging one end of the shaft by which the shaft is delicately supported'to have free axial oscillating l movement. Upon the standard is mounted a bracketlZ 0f insulating material provided with 'a spring contact tongue l3 that is electrically connected with the continuation 2 of the audio-circuit wire 2, and upon the shaft i0 is mounted a finger II that overlaps and, upon turning of the shaft inone direction, has contact with the tongue. Threaded stops [5 and I6 oppositely disposed in the bracket are arranged to limit movement of the finger therebetween.

Upon the bracket are mounted major and minor electro-coils, A and B, disposed obliquely respecting the shaft it) in parallel planes and encompass said shaft which extends through their axes at the medial points thereof.

Upon the shaft ID are mounted a pair of iron vanes 11 and I8 that slantoppositely with respect to each other and are located within the magnetic fields of the respective coils, so that upon energizing oi the coils, torque is exerted on the shaft in opposing directions.

Upon a stud l9 projecting from the base:9 is mounted a regulating lever 20, one end of which is provided with a handle2l and its opposite end 22 is slotted and extends astrideand secures the outer end 23 of a balance spring 24 that consists of a coiled metal band. The inner end of the spring is secured to the shaft l0. By adjustment of the lever 20 upon the stud, angularly with respect to the axis of the shaft, the shaft is normally held, through the medium of the spring-so that the contact finger M is disposed in neutral position cut of contact with the tongue l3 whereby the secondary audio circuit through the continuation 2", tongue l3, contact finger i4, shaft l0, base 9, and continuation 3" is then open.

The conductors 2 and 3 have continuations 25 and 26 respectively between which is connected an'adjustable resistance 21 provided with an adjustable contactor 28, and also there is connected between the continuations 25 and 26 a bridge tone circuit in which are included the resistances 21 and 29, condenser 30 and a choke coil 3|. The contactor 2B is connected with one terminal of the minor coil B by a conductor 32, the opposite terminal of said coil being connected with the continuation 25 at a point between the resistance 29 and the condenser 30 by a conductor 33. Preferably, the continuation 25 has connected therein a manually operated switch 34 located between the connections therewith of the adjustable resistance 21 and the audio circuit wire 2.

The opposite terminals of the major coil A are connected respectively with the continuation 25 and the conductor 3 respectively by means of branches 35 and 36, and there is connected in said branch 36 another variable resistance 31.

In this system there are included a primary audio circuit (22'-548-3 and 3); a secondary audio circuit (22'--542--l3-l433' and 3;)

a coil A energizing circuit (2 a5 as-a1 and 3) a coil B energizing circuit (225-293332-28-21-26 and 3) and a tuned bridge circuit (21-29-30 and 3|) connectedly related with the coil B energizing circuit, designed for sensitiveness to a definite signal cycle. By this arrangement, when the switch 34 is closed the normal output flow of current. from the receiving set I is distributed-to the coils A and B through their respective energizing circuits and to the phone 4 through the primary audio circuit. By adjustment of the variable resistance member 31, the volume of how through the respective coils is brought to equality and their magnetic effect thus balanced; By adjustment of the lever 20 the shaft l through the medium of the balance spring. 24 is turned to neutral position so the switch (l3-l'4) is open. Upon occurrence of each signal impulse, in the output from the set I at a selected fre- 'quency, the flow of current through the coil A is thereby increased, while coincidentally the signal impulse is intercepted in the bridge circuit because of resonance occasioned and is therefore eliminated from the energizing circuit of the coil B. Under this circumstance, the coils A and B become unbalanced, the coil A having superior force in turning the shaft 10 in switch closing direction, thus'resulting in closing of the secondary audio circuit. Concurrently, therewith, an'y' radio frequency generated at the switch contacts l3l4 is bypassed by the condenser 1 and thus eliminated from the input circuit of the receiver. Thus, upon each signal impulse the secondary audio circuit is closed and the phone 4 energized enabling the operator to detect the signal. u A

"By adjustment of the variable resistance the volume of current passing through the phone is modified as desired.

Operation In using the invention, the output or the receiving set 'I is admitted to the primary audio circuit while the switch 34 is open, and the volume is reduced by adjustment of the resistance :member 5 50 Sound is faintly audible through the phone 4. The switch 34 is then closed and the 'contactoi' 28 is adjusted to a point where the resistance of the two arms of the bridge cirjcuit are in balance. The coils A and B are then balanced by adjustment of the resistance mew ber 31', and the switch I3--I4 is positioned in neutral or open position by adjustment cf the lever 20.

The minor coil B, upon closing of the switch 34, is brought into connection with the primary audio circuit, the flow of current therethrough being modified by the resistance 29 and the adjustable resistance 21, and is additionally affected by the condenser 30 and the choke coil 3| of the bridge between the conductor 33 and the continuation 26. By these arrangements the flow of current through the coils A and B differ: The current passing through the major con A, bears the characteristics of the audio output flow from the telegraphic receiver and includes the signal and static influences, while the flow of current through the minor coil B is distinguishable in that it is characterized only by the eifects of the static influence emanating through the output of the telegraphic receiver. The currents thus differing in character, passing through the coils A and B, create opposite or varying influences upon the respective vanes l1 and I8, whereupon, the shaft is angularly turned upon its axis, in one direction or' the opposite, according to the greater or lesser magnetic influence of the coils on the vanes.

Operation of the make and break circuit is influenced because of torque exerted oppositely by current passing through the major and minor coils and their co-related vanes on the shaft l0. Ordinarily, due to the unequal opposing influences of the currents passing thro'u'ghthe major and minor coils upon their respective vanes, the contact finger II on the shaft is moved into or out of contact with the spring tongue 1'3, whereupon the make and break circuit is closed or opened accordingly in unison with the signal impulses passing through coil A, to which the telephonic receiver is responsive. Variations from the particuiar construction above disclosed may be resorted to by the exerelse of skill in the art, without departure from the spirit or scope of the invention, and the following claim is intended to be inclusive of such variations.

What I claim is:

In a static eliminator for a radio telegraphic receiver, an electrically operated make and break device consisting of a standard having thereon a stationary contact member, an oscillatorpivoted in said standard provided with a finger "enga'geable with said member, said member and finger being electrically "connected in the audio circuit of said receiver, major and minor electr c coils positioned on said standard in slanting parallel planes, iron vanes secured on said oscillator in oppositely slanting planes and disposed respectively in the magnetic fields of said coils so the oscillator is influenced oppositely when the polls are energized, a balance spring on the oscillator provided with an adjuster therefor, and electrical means associated with said audio circuit includ ingindiv'idual circuits for said coils through which the -m'aj orc'oil'is energized by current derived from "s aidau'dlo "circuit characterizedbysimaland static influences, and the minor coil is energized by cur rent derived from the same source characterized exclusively by the static influence whereby the static influences in said coils counterbalance e'ach jo't'h'er and the oscillator is actuated by the signal influence of the current passing through the major coil. 7

THOMAS -W. 

